Fuel processing systems include a fuel processor that produces hydrogen gas or hydrogen-rich gas from common fuels such as a carbon-containing feedstock. Fuel cell systems include a fuel processor and a fuel cell stack adapted to produce an electric current from the hydrogen gas. The hydrogen or hydrogen-rich gas produced by the fuel processor is fed to the anode region of the fuel cell stack, air is fed to the cathode region of the fuel cell stack, and an electric current is generated.
In some fuel processors, the feedstock to the fuel processor includes only a single component. Examples of these fuel processors include electrolysis units, in which the sole feedstock is water, and pyrollysis and partial oxidation reactors, in which the sole feedstock is a hydrocarbon or alcohol. In many fuel processors, however, the feedstock includes more than one component, such as water and a carbon-containing feedstock. Examples of carbon-containing feedstocks include an alcohol and a hydrocarbon. When the feedstock includes more than one component, these components need to be mixed and delivered to the fuel processor. Because the feedstock does not include a single component, the two or more components forming the feedstock will be present in various percentages or fractions, with the relative mix of these percentages affecting the operation and/or efficiency of the fuel processor and the makeup of the product streams.